The present invention relates to a tape loading apparatus used, for instance, in a magnetic recording/reproduction device of the VHS system, for drawing out a magnetic tape from a tape cassette with a tape guide pin and placing the tape at a predetermined angle around a head cylinder having a built-in rotary magnetic head for recording and reproducing. In particular, the invention aims at providing a concrete structure of a tape loading apparatus that reduces the space occupied by employing a toggle mechanism.
FIG. 22 and FIG. 23 show a conventional tape loading apparatus employing a toggle mechanism for magnetic recording/reproduction devices used in VHS systems.
In FIG. 22, a head cylinder 1 is provided with a built-in rotary magnetic head (not show in the figure), and a tape cassette 2 contains a magnetic tape 13. Guide channels 3 are formed in a chassis base 12 below the tape cassette 2 and on both sides of head cylinder 1.
As shown in FIG. 23, a movable carriage 4 is provided with a tape loading post 5 and a tape guide pin 6 with a predetermined space between them on an upper surface, and a first guide pin 71 and a second guide pin 72 on a lower surface, both engaged slidably in the guide channels 3. A driving wheel 8 for the tape loading apparatus rotates reversibly as it is driven by a motor (not show in the figure).
The operation of the tape loading apparatus employing a toggle mechanism during loading of the tape will be described with reference to a tape takeup side (which is a right side of the head cylinder 1), in this tape loading apparatus.
A first arm 9 rotates about an arm spindle 10 in an interlinked motion in response to rotation of the driving wheel 8, and one end of a second arm 11 is linked rotatably to another end of the first arm 9. The other end of second arm 11 is rotatably and coaxially connected to the second guide pin 72 on the under surface near a tail end of the movable carriage 4. In other words, the first arm 9 and the second arm 11 constitute a toggle mechanism, which extends and retracts in an interlinked motion in response to the rotation of the driving wheel 8. An extension and retraction of the toggle mechanism moves the movable carriage 4 from underneath of the tape cassette 2 to a position adjacent a side face of the head cylinder 1 along the guide channel 3, or vice versa in a reversed motion. This movement of the movable carriage 4 carries out a tape loading operation by enabling the tape loading post 5 to pull out the magnetic tape 13 from the tape cassette 2, and to place the tape around the head cylinder 1 at a predetermined angle. Alternatively, it carries out an unloading operation by retracting the pulled-out magnetic tape 13 into the tape cassette 2.
In a final step of the above tape loading operation, the movement of the movable carriage 4 is limited at a position where a V-shaped portion provided at a leading end of the movable carriage 4 comes in contact to a cylindrical stopper 22 secured to the chassis base 12. Because a connecting point (the second guide pin 72) of the second arm 11 to the movable carriage 4, at this point of time, is in a near side to the head cylinder 1 with respect to a straight line drawn in phantom between the arm spindle 10 and the stopper 22, a thrusting force of the toggle mechanism causes the movable carriage 4 to turn about the stopper 22 in a direction where the tape guide pin 6 becomes even closer to the head cylinder 1, after the above contact with the stopper 2. Therefore, this structure places the magnetic tape 13 around the head cylinder 1 at a predetermined winding angle of 180xc2x0 or greater. As shown in FIG. 23, the movable carriage 4 stops at this point when the second guide pin 72 is pressed against a restrictive end 31 formed in continuity with the guide channel 3 at a side close to the head cylinder 1.
What has been described above relates to the toggle mechanism of the tape takeup side with respect to the head cylinder 1 in FIG. 22. However, a toggle mechanism of a tape supply side (i.e. a left side of the head cylinder 1), also includes a similar structure, and it is operated by a driving force of the same driving wheel 8. Reference numerals 14, 15, 16, and 17 respectively represent a sound erasing head 14 (for post-recording), a sound and control signal head 15, a capstan 16, and a pinch roller 17. A reference numeral 161 represents a direct drive motor for driving a capstan 16 or a capstan flywheel driven by an ordinary motor (not show in the figure), and reference numerals 18, 19, and 20 are respective tape guide posts (rollers).
Although the loading operation and the unloading operation of the magnetic tape can be carried out by the above mechanism, there has been a problem that it is difficult to reduce an overall size of the magnetic recording/reproduction devices for reasons that: (1) a space occupied by the toggle mechanism is too large in order for the movable carriage 4 to turn in the direction of becoming closer to the head cylinder 1 by the thrusting force of the toggle mechanism, and to place the magnetic tape 13 around the head cylinder 1 at the predetermined winding angle of 180xc2x0 or greater; and (2) overall dimensions of the entire magnetic recording/reproduction device need to be sufficiently large in order to avoid an interference with the other functional components such as the sound erasing head 14, the sound and control signal head 15, the capstan 16, the direct drive motor for the capstan 16, or the capstan flywheel driven by an ordinary motor (not show in the figure), the pinch roller 17, and the like.
In view of the afore-mentioned problems, the present invention is intended to provide a toggle mechanism for a tape loading apparatus that reduces a space it occupies, yet it is capable of turning a movable carriage easily in order to move a tape guide pin on the movable carriage closer to the head cylinder.
A tape loading apparatus of the present invention includes: (a) a chassis base provided with a head cylinder, including a guide channel having a first position and a second position; (b) a movable carriage provided with a tape loading post and a tape guide pin on an upper surface, and a first guide pin and a second guide pin on an under surface, both engaged slidably in the guide channel; (c) a toggle mechanism, one end of which is rotatably connected to the movable carriage, and the other end positioned at one side of the guide channel close to the head cylinder, wherein an extension and retraction movement of the toggle mechanism moves the movable carriage reversibly between the first position and the second position in a sliding manner along the guide channel; and (d) movable carriage turning means for turning the movable carriage in a direction, where the tape guide pin moves close to the head cylinder, at a position in proximity to the second position.
In this structure, the movable carriage turning means forcibly turns the movable carriage before completion of the loading operation, in order to place a magnetic tape at a predetermined angle around the head cylinder, by moving the tape guide pin provided on the movable carriage. Thus, the structure is able to realize a reduction in size and cost of the entire magnetic recording/reproduction device, since: (1) it does not require a complex toggle mechanism because an arm spindle, serving as a rotary axis, of the first arm composing the toggle mechanism can be arranged between the guide channel formed in the chassis base and the head cylinder; and (2) it can reduce an area or space occupied by the toggle mechanism and its movement. The structure can achieve a miniaturization, which is indispensable especially for a combination camera and magnetic recording/reproduction unit.